Orobophana musiva (Gould)

Mosaic Orobophana Snail (Orobophana musiva)

This species was described in 1847, it is found in Fiji, in Samoa, and obviously in Tuvalu as well.

The Mosaic Orobophana Snail is found under decaying vegetation at low elevations, very often near the coast.

It is a very small species, the shells reach heights of only about 0,2 cm, they vary in color from several shades of yellow and orange to reddish-brown.

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References:

[1] Robert H. Cowie; Rebecca J. Rundell: The land snails of a small tropical island, Aunu’u, American Samoa. Pacific Science 56(2): 143-147. 2002

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Ostodes exasperatus Girardi

Large Ostodes Snail (Ostodes exasperatus)

This species was described in 1978.

The species is known from the islands of Savai’i and ‘Upolu, however, these two populations differ from each other in so far that the males from ‘Upolu are larger than the females, while the situation is reversed in Savai’i.

The shells reach a height of about 0,9 to 1,3 cm and a width of up to 1,3 cm. [1][2]

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References:

[1] E. L. Girardi: The Samoan land snail genus Ostodes (Mollusca: Prosobranchia: Poteriidae). The Veliger 20(3): 191-246. 1978
[2] Robert H. Cowie: Catalog of the nonmarine snails and slugs of the Samoan Islands. Bishop Museum Bulletin in Zoology 3. 1998

Minidonta extraria Cooke & Solem

Strange Disc Snail (Minidonta extraria)

This species was described in the year 1976 from three specimens, of which one was found on the island of Akamaru, one on the island of Mangareva, and one on the island of Taravai.

The shells reach an average size of 0,29 cm in diameter.

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References:

[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
[2] Ahmed Abdou; Philippe Bouchet: Nouveaux gastéropodes Endodontidae et Punctidae (Mollusca, Pulmonata) récemment éteints da l’archipel des Gambier (Polynésie). Zoosystema 22(4): 689-707. 2000

Justin Gerlach: Partula – Icons of Evolution

Justin Gerlach: Partula – Icons of Evolution

The genus Partula, extremely rich in Polynesian species, will soon get it’s newest monograph (I’m not sure, but it may be the first monograph at all).

The book, written by Justin Gerlach and named “Partula – Icons of Evolution”, is nearly ready to be published, but the project can still be supported.:

https://www.kickstarter.com/projects/507116283/partula-icons-of-evolution

 

Endodonta apiculata Ancey

Pointed Disc Snail (Endodonta apiculata)

The Pointed Disc Snail, which was restricted to the island of Kaua’i, Hawaiian Islands, was described in the year 1889.

The shells of this species reached an average size of 0,6 cm in diameter. [1]

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The genus Endodonta contains a little more than 10 species, all, except probably for one, are now obviously extinct.

The destruction of large areas of the native lowland habitats led to their extinction, and introduced invasive species, especially several aggressive ant species (for example the Red Fire Ant (Solenopsis invicta Buren) or the Little Fire Ant (Wasmannia auropunctata (Roger))) are a very serious threat to the last remaining endemic snail species, and are blamed for the extinction of many island endemic species. [2]

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References:

[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
[2] Norine W. Yeung; Kenneth A. Hayes: Update on the status of the remaining Hawaiian land snail species Part 4: Punctidae and Endodontidae. 2016

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edited: 23.03.2017

Partula otaheitana (Bruguière)

Otaheite Tree Snail (Partula otaheitana)

The Otaheite Tree-Snail, whose name refers to it as being endemic to the island of Tahiti (Otaheite is an old name of the island), was described in 1792.

This species is nowadays highly threatened with extinction, yet somehow managed to withstand the introduction of the Rosy Wolf Snail (Euglandia rosea (Férussac)) to Polynesia, that had cost the lives of so many other endemic snail species.

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The Otaheite Tree-Snail is split into four so called anatomical forms, which overlap or are linked to each other by intermediate forms, and which are each restricted to certain parts of Tahiti. They may or may not be treated as subspecies, and are named as Partula otaheitana ssp. crassa Garrett (in the western part of Tahiti nui), Partula otaheitana ssp. otaheitana Bruguière (in the northern part of Tahiti nui), Partula otaheitana ssp. rubescens Reeve (in the eastern part of Tahiti nui as well the northern part of Tahiti iti), and finally Partula otaheitana ssp. sinistrorsa Garrett (in the largest part of Tahiti nui, including the center of the island and the southern part, as well as the most parts of Tahiti iti).

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References:

[1] Justin Gerlach: Icons of Evolution: Pacific Island tree-snails, family Partulida, Phelsuma Press, Cambridge U.K. 2016

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Photo: Antonio Machado; by courtesy of Antonio Machado

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edited: 31.08.2017

Anceyodonta andersoni Cooke & Solem

Anderson’s Disc Snail (Anceyodonta andersoni)

Anderson’s Disc Snail was described in the year 1976.

The species was originally known only based on specimens that had been collected in 1934 on the island of Mangareva, but was subsequently (in 2000) recorded in form of subfossil shells from Taravai, Mangareva’s neighbor island, as well.

The shells of the species reached an average size of 0,29 to 0,36 cm in diameter.

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References:

[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
[2] Ahmed Abdou; Philippe Bouchet: Nouveaux gastéropodes Endodontidae et Punctidae (Mollusca, Pulmonata) récemment éteints da l’archipel des Gambier (Polynésie). Zoosystema 22(4): 689-707. 2000

Powelliphanta marchanti (Powell)

Marchant’s Predatory Snail (Powelliphanta marchanti)

This species is restricted to the western Ruahine Ranges on the North Island of New Zealand, where it can be found amongst leaf litter in native forest.

Like its congeners, also this is a carnivorous species that feeds upon invertebrates, preferably on earthworms.

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Marchant’s Predatory Snail is in decline and highly endangered.

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Photo: V. Vercoe

(under creative commons license (4.0))
http://creativecommons.org/licenses/by/4.0

Partula lutea (Lesson)

Yellow Tree Snail (Partula lutea)

This variably colored species was described in the year 1831.

The species was endemic to the island of Bora Bora, Society Islands, where it was the only member of its genus, and where it was still numerously found in the 19th century on the stems, branches, and leaves of the native vegetation.

The shells reached a height of nearly 2 cm and was usually pale yellowish to light brown with the apex being of the same color or slightly darker.

The Yellow Tree-Snail is now extinct. [1]

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The same species was introduced to the island of Maupiti sometimes after 1929, from where it is known, however, only from subfossil shells, found and photographed in 2010, 2012 and 2017 by J.-F. Butaud, J. Gerlach and others.

The species is extinct on Maupiti as well. [1][2]

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References:

[1] Justin Gerlach: Icons of Evolution: Pacific Island tree-snails, family Partulida, Phelsuma Press, Cambridge U.K. 2016
[2] Justin Gerlach: Partula survival in 2017, a survey of the Society Islands

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Depiction from: ‘George W. Tryon; Henry A. Pilsbry; u.a.: Manual of Conchology. Second Series: Pulmonata Vol. 20, Caecilioides, Clessula and Partulidae. Index to Vols. 16-20. 1909-1910’

(public domain)

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edited: 31.08.2017